Composting is a natural process where kitchen and yard wastes decompose
into a dark, nutrient-rich, earth-smelling soil conditioner. Perhaps
you’ve considered backyard composting but live in a high rise or don’t
relish the thought of tramping through your garden in the middle of a
winter blizzard. If so, worm composting is the option for you.
is worm composting?
Worm composting is simply composting with worms. The best kind of
earthworm to use is an Eisenia
foetida, or a Lumbricus
commonly called redworm. These worms are incredible garbage eaters!
They eat and expel their own weight every day; even a small bin of
redworms will yield pounds of rich sweet-smelling compost. Finished
compost can be harvested in as little as two to three months. Redworms
(aka “red wigglers”) are extremely prolific. It takes about three weeks
for fertilized eggs to develop in a cocoon from which two or more young
worms can hatch. In three months the worms are sexually mature and will
start breeding. Within a year you’ll be able to give worms away to get
a friend started!
can I get a worm bin?
For 1 or 2 people a plastic storage bin can be purchased from a
hardware store. Make sure the bin has a lid. For 4 to 6 people, a
design sheet to build your own bin from wood is attached (see “Building
a worm compost bin.”)
|1 or 2
||1ft x 1.5ft
|2 or 3
||1ft x 2ft x
|4 to 6
||2 to 3 lbs.
||1ft x 2ft x
do I set up the bin?
For the plastic bin, drill 8-10 holes (approx. 1/4”) in the bottom of
the bin for adequate drainage. Drill 4-6 in the lid. Line the bottom
with fine nylon mesh to prevent the worms from escaping. Raise up the
bin on some type of blocks with a tray underneath. After the bin is
constructed you need to think about bedding for the worms. Redworms can
survive and breed in many kinds of bedding materials. The “red wiggler”
is a manure worm and will eat its own bedding. Materials such as fall
leaves (best if shredded), shredded newspaper (hand shred into long
thin strips), ground cardboard, aged animal manure, or organic peat
moss can all be used. (Make sure to mix peat moss with other bedding as
it is too acidic to use alone.) It is important to keep the bedding as
moist as a well-wrung sponge. Since a worm’s body is made up of about
75% water it is important to be sure that the bedding is prepared with
the same 75% moisture content, this will allow the worm to breathe.
Using a mixing container, put in about one-half of the bedding and
one-half of the water required, mix. Add two handfuls of soil and what
is left of the bedding and water and mix again until the bedding is
moist enough. Dump entire mixture into the worm bin. Now it is time to
add the worms, dump the whole container of worms onto the bedding and
spread around. Garbage may be
buried as soon as the worms are in the bedding.
can I get Redworms?
As stated previously, redworms should be used in composting. This type
of worm is most efficient because its natural environment is decaying
matter, they will be able to process this organic material quickly.
This special worm may be shipped through a delivery service.
Redworms can be ordered from the following suppliers and outlets:
3815, Rt. 96
Shortsville, NY 14548
|Cape Cod Worm Farm
30 Center Ave.
Buzzards Bay, MA 02532
PO Box N122
Westport, MA 02790
|The Green Planet*
57 Lincoln St
(617) 332- 7841
10332 Shaver Rd.
Kalamazoo, MI 49002
(616) 327- 0108
|Beaver River Associates*
P.O. Box 94
W. Kingston, RI 02892
In nature, redworms can be found in decaying leaves, manure piles or
other organic material, such as compost piles. If you have access to
such areas, you can collect your own redworms. A few handfuls are
enough to start a bin, but add only small amounts of food scraps until
the worm population increases enough to handle more (3-4 months).
*The above vendors offer several types of commercial worm bins and
“worm kits” currently on the market, in addition to classroom curricula
on worm composting. A “worm kit” includes a bin, worms, and
do I feed them?
Worms will eat just about any type of kitchen waste including
vegetables, fruits, coffee grinds, tea bags and eggshells (crushed.) Do
not add meat or meat byproducts. Bury the food scraps completely,
that they are always covered by bedding; this prevents
odors and fruit flies. Don’t add more food scraps than the worms eat in
several days. The worms can’t eat the food until it starts to
decompose, so it may take a few months for the bin to get up to speed.
For fastest decomposition, chop the food scraps into small pieces.
ecology of a worm bin.
The decaying materials in a compost pile may attract some critters,
other than the redworms. This is a common situation and is not a bad
thing as many may see it. Since these other bugs do play a role in
breaking down the organic matter found in the compost bin, they are
actually helping the process. Some of these organisms include
centipedes, millipedes, mites, fruit flies, ants, and some others.
worms live outside during colder months?
Worms prefer temperatures between 40 and 80 degrees Fahrenheit.
If you live in an apartment building they can live quite happily out on
the balcony until temperatures drop to 40 degrees. After that they
should be taken indoors. Basements or garages that don’t freeze are
good locations for worm bins.
can I harvest the finished compost?
After about 3 months you’ll notice that the volume of materials has
dropped substantially and the original bedding is no longer
recognizable. At this point the finished compost and worms can be moved
over to one side of the bin and now bedding added to the vacant side.
• Put new food waste into the fresh
bedding only so the
worms will move
from the finished compost in search of new food.
• After two weeks or so remove the lid under a bright light source.
• Scoop out the finished compost a few layers at a time and place in a
plastic bag, or bucket, until you’re ready to use it.
can I use the finished compost?
Vermicompost will provide nutrients to your plants and will help the
soil hold moisture. The compost created contains humus, decomposing
matter, and worm castings. The mixture is often used as a dressing
during the spring, but can also be used later. The ending material will
be dark, crumbly, and earthy-smelling. A few chunks may be recognized
as food waste or bedding, but when it is dried it will be a smooth,
dark mixture. It can be used in a number of different ways:
1 - Sprinkle into a seed row when planting.
2 - When transplanting, add a handful of soil to the hole you have dug
for the plant.
3 - Use as a top dressing, sprinkling the compost around the base of
4 - Mix with potting soil (half-and-half) for house plants.
Worm die-off or escaping
If you notice the worm population dwindling, or worms crawling
all over the bin trying to escape, check for the following:
• Bin is too wet and worms are
drowning. Add dry bedding,
increase airflow in the bin creating
ventilation holes, or leaving the lid off for a while.
• Bin is too dry and worms dry out.
Moisten bedding. Place a strip of
plastic over the bedding to retain
• Only castings left in bin.
Once the worms devour all of their
food and bedding, they will start to
eat their own castings, which are poisonous to them. Time to harvest
and add fresh bedding.
• The bin is exposed to extreme
temperatures. The bin should
not be exposed to temperatures
above 77° F or below 50° F. The worms thrive in temperatures
from 50 to
77 degrees F.
NOTE: Dead worms decompose rather
quickly. If you do not monitor the
above conditions you can have a dead box of worms before you even
If your worm bin has an unpleasant odor, one of the following
may be the culprit:
• Bin is too wet. Do not add
any water or foods with a high percentage of water (e.g., melons,) do
add more dry bedding.
• Bin does not get enough air.
Anaerobic bacteria (bacteria which thrives without air) is smelly. To
aerate, add fresh bedding and mix bin contents daily.
• The food waste is naturally smelly.
For instance, we have found that onions and broccoli do not smell very
pleasant when they decompose in the worm bin. Simply remove any food
source that smells bad from the bin.
• Bin contains non-compostables.
Meat, bones, dairy and oily products should not be fed to the worms
because these items become rancid when decomposing.
If you’ve found fruit flies living around and in your worm bin,
you may get rid of them using one or both of the following methods:
• Make a trap. Place ½
cup of beer or honey in a jar. Poke a hole in the corner of the a
sandwich bag with a pen. Tighten the bag around the rim of the jar with
a rubber band. The open bag should be above the level of the contents
of the jar. The flies are attracted to the beer or honey and find their
way in, but not their way out!
• Vacuum them. When you open
the lid you will see fruit flies crawling and flying about. Quickly
vacuum the crawling flies and those that land nearby.
Worms Eat My Garbage,
Mary Appelhof, Flower Press, Michigan, 1982, 100
pp. Available from:
COMPOST ONTARIO, Recycling Council of Ontario
489 College St.,Suite 504
Toronto, Ontario M6G 1A5
Bonhotal, Jean. Kransny, Marianne E. Composting:
Wastes to Resources.
Cornell Coopertive Extension, Ithaca, New York. 1994